/*
Implement regular expression matching with support for '.' and '*'.

'.' Matches any single character.
'*' Matches zero or more of the preceding element.

The matching should cover the entire input string (not partial).

The function prototype should be:
bool isMatch(const char *s, const char *p)

Some examples:
isMatch("aa","a") → false
isMatch("aa","aa") → true
isMatch("aaa","aa") → false
isMatch("aa", "a*") → true
isMatch("aa", ".*") → true
isMatch("ab", ".*") → true
isMatch("aab", "c*a*b") → true
*/

class Solution {
public:
    bool isMatch(const char *s, const char *p) {
        if (*p == '\0') return *s == '\0';
        // next char is not '*': must match current character
        if (*(p+1) != '*') {
            return ((*p == *s) || (*p == '.' && *s != '\0')) && isMatch(s+1, p+1);
        }
        // next char is '*'
        while ((*p == *s) || (*p == '.' && *s != '\0')) {
            if (isMatch(s++, p+2)) return true;
        }
        return isMatch(s, p+2);
    }
};
